FIG. 1 is a diagram for describing self-interference occurring in a relay 100 that transmits first data to a terminal 140 via a single transmit antenna, and receives second data from a base station 130 via a receive antenna, using the same frequency band.
Although description will be made based on a downlink of a radio communication system in FIG. 1, the present invention may be similarly applicable even to an uplink of the radio communication system.
Referring to FIG. 1, the relay 100 may transmit the first data to the terminal 140 using a transmit antenna 120. The relay 100 may receive the second data from the base station 130 using a receive antenna 110. Here, the relay 100 may use the same frequency band for the above transmission and reception.
The first data transmitted by the relay 100 using the transmit antenna 120 may be directly input into the receive antenna 110 as indicated by an arrow indicator 160. Also, as indicated by another arrow indicator 170, the first data may be reflected by a building 150 around the relay 100 to thereby be input into the receive antenna 110.
When the relay 100 transmits the first data and receives the second data using the same frequency band in the same time slot, the reflected and thereby received first data may become strong interference against the relay 100. Therefore, the relay 100 may not receive the second data. It is referred to as self-interference, which may be a major cause to deteriorate a data throughput.